The Battlefield Blog has details on the Squad Rush multiplayer mode in Battlefield Bad Company 2, DICE's upcoming military shooter sequel. They offer a gameplay trailer on the YouTube and describe the mode thusly: "Squad Rush puts a squad of four players versus another squad of four players for a max of eight player matches in this intense one crate/two base infantry only version of the Rush gamemode." There are also details on how this mode will be exclusive for 30 days to preorder customers on GameStop, though this only applies to console versions in North America. For PC owners they say: "No Exclusive Access on PC, however we'll make the gamemode available at launch instead."

I would expect that this is what is holding up an announcement for BF3.

Yes I suspect that as well. Once the game is out the door, I think we'll hear something. It's been in development for how long? Four years?

I don't think we hear anything until 1943 for PC is released, DICE says it is still coming. There is also Medal of Honor coming out for PC so I think that may stop them from showing anything BF3 related. I hope my guess is wrong, I wants a designed for PC Battlefield game, DICE!